Process for preparing lubricating oils



United States Patent .Dfiice 2,849,385 Patented Aug. 26, 1958 PRocEssnon PREPARING LUBRICATING OILS James H. Kirk, Dyer, Ind, assignor toSinclair Refining Company, New York, N. Y., a corporation of Maine NoDrawing. Application May 2, 1955 Serial No. 505,549

4 Claims. (Cl. 196-147) This invention relates to aircraft lubricationand, in particular, relates to an improved method forproducingnon-additive lubricating oil compositions especially useful forlubrication of aircraft engines.

The production of lubricating oil compositions is in many respects anempirical art notwithstanding extensive study of the field. Often eachlubricationproblem requires a composition conforming to specialspecifications; and differing compositions frequently require differentprocessing steps to produce. Thus, what may be applicable to a given oilfraction from one source isfrequently without significance in preparinga lubricating oil composition conforming to the samespecifications froma fraction originating from entirely different basic stock.

Of the problems of lubricating oil performance, one peculiar to theaircraft field is that failure to lubricate properly in service cannotbe tolerated since a plurality of chances may not exist. Hence, specialtests have'been established by some engine manufacturers as a control onpermissible limits of certain properties of the comcarefully watched.Frequently, in manufacturing a saleable product the lead loss must beless than 50 milligrams. cautions or which need to be tested frequenltyincrease maintenance costs and this fact can militate against their use.

Of course, compositions requiring special pre-" I have now discovered animproved method whereby aircraft engine non-additive lubricating oilcompositions can be produced which are characterized by a low corrosionindication by the MacCoull-Ryder test. The improved method involvessequential treatment of each component of the lubricating oilcomposition with defined quantities of particular clays withinprescribed temperature conditions. The lubricating oil compositionsproduced in accordance with the invention contain about 5 to volumepercent refined neutral oil and about 50 .to 95 volume percent of arefined heavy mineral lubricatingoil fraction of about 80 to 200 SUS at210 F., e. g. bright stocks. The components to be blended are obtainedby contacting with an acid activated clay, for example acid activatedmontmorillonite, followed by contacting with a neutral clay such asfullers earth. Thus the sequential treatment involves dual clay contact.Each component can be contacted separately and the resulting materialsblended, or the acid activated clay contacting can be accomplished oneach component separately, the resulting components blended and thenthe, resulting blend subjected to the neutral clay contact.

' Thus the essence of the present invention comprises treatment of thecomponents to be used in the lubricating various. crudes. O

oil composition with particular clays in a defined manner. Morespecifically, the heavy lube oil stock is contacted with acid treatedclay, i. e. acid activated montmorillonite', in a quantityv of about 4to 8 poundsper barrel, and preferably 6 or 7 pounds per barrel at atemperature, of about 500 to 600 F., especiallySSO" F. The neutral oilcomponent is contacted with about 1 to- 5 pounds of acid a'ctivated clayper barrel at a temperature of about 325 to 450 F. Particularlyadvantageous results are achieved when employing 2 to 4 pounds of theacid activated clay, and especially 3 pounds, at a temperature of atleast 400 F. The neutral clay contacting step is substantially identicalfor each component although; as indicated before, it can be conducted oneach component separately or on the acid activated clay treatedcomponents jointly. Advantageously, 2 to 15 pounds and preferably threepounds of neutral clay are employed per barrel of oil treated at atemperature of about 275 to 350 F and preferably 325 F. At the end ofeach contacting step light, unstable ends having boiling points of up to700 R, which are principally cracked unsaturates, are removed,advantageously by steam stripping preferably at the temperature of claycontact so that temperature adjustment need not be made. Removal ofthese light ends is essential after the acid activated clay treatmentand is highly desirable after the neutral clay treatment also. Suchstripping preferably is accomplished in the presence of the clay, thoughstripping also can be effected after separating the clay from the oilcomponent. The materials removed are detrimental since they are subjectto oxidation and-since they act as oxidation promoters.

The clays which can be employed forthe contacting steps producingcompositions of the present invention are known articles of commerce.For example a typical acid activated clay is acid activatedmontmorillonite and is commercially available as the various Filtrols.Suitable neutral clays include bauxite and fullers earth and aparticularly desirable commercially available neutral clay is known asattapulgus clay.

As has been pointed out above, each clay contacting step is conducted inthe presence of a defined amount of a particular clay within certaintemperature limitations. It has been discovered that treatment of theneutral oil with quantities of the defined clay which do not conform tothe prescribed limits can be detrimental to the resulting composition.For example, in the instance that an insufficient amount of clay isemployed, the treatment fails to reduce corrosiveness sufiiciently; theuse of an excess quantity of clay tends to increase corrosiveness overthat previously obtained or over that originally evidenced.

It has also been discovered that the use of low temperatures outside thedefined range can have a similar effect. In other words both temperatureand quantity of clay must be correlated in my invention to result in thecritical sequentialoperation which is essential to secure a satisfactoryproduct. I i

The contacting steps employed in the invention are effected in anymanner known to the art. Particularly satisfactory results-are obtainedby slurrying the clay with the oil fraction at the proper temperature,agitating to insure that all of the oil present is treated and thenremoving the solids from the slurry to secure the treated product. Thesolids can be removed by settling, filtration or other means. Ifdesired, filter presses or other apparatus designed to speed theoperation can be employed.

Neutral oil and bright stocks are well-known commercially availablemineral oil fractions obtainable from Generally refined neutral oils areobtained as a solvent, e. g. phenol, extracted," dewaxed distillate froma vacuum still distillation of a reduced crude. For purposes of thepresent invention, the neutral oil must have a viscosity of about '300to 600 SUS at 100 F. To secure a neutral oil withthis viscosity, theneutral oil is steam stripped of sufficient light ends until the desiredviscosity is obtained. Bright stock normally is obtained as thedeasphalted, solventextracted, dewaxed 80 to 200 SUS at 210 F. heavyresiduum from a distillation of reduced crude. In certain crude oilrefining operations, bright and cylinder stocks are distillates.

The invention will be described further in conjunction with thefollowing specific examples. It should be understood that the detailsdisclosed are not to be considered as limiting the invention.

EXAMPLE I A straight run neutral oil obtained vfrom a vacuum stilldistillation of a Mid-Continent reduced crude oil was phenol extractedand dewaxed by the methylethylketone process according to conventionalprocedures. The resulting neutral oil had a viscosity of 440 SUS at 100F. and a viscosity index of 95.5. The neutral oil was heated to 400 F.and about 3 pounds of Filtrol No. 70 per barrel of oil then was slurriedwith the oil. The slurry was agitated and steam at 400 F. was passedthrough to strip out light ends. The resulting mass was filtered and thetreated neutral oil recovered.

A straight run bright stock fraction obtained .upon propanedeasphalting, phenol extracting and methylethylketone dewaxing a heavylubricating oil residuum resulting upon vacuum distilling aMid-Continent heavy reduced crude was employed in this example. Thebright stock had a viscosity of 162 SUS at 210 F. and a viscosity indexof 95.3. The bright stock was heated to 600 F. and Filtrol No. 70 wasadded in an amount equivalent to 6 pounds per barrel. After a period ofagitation, steam at 600 F. was passed through the Table I FiltrolFiltrol Blend con- Uncon- 0011- of filtrol Dual MacCoull-Ryder test (5hrs. tacted tacted tacted conconat 320 F., copper catalyst) neutralbright bright tacted tacted oil stock stock fracblend tions Lead bearingloss, mgs 1 1, 203 1 204 1 21. 4 276 1 15. 8 Viscosity increase (SUS/210 F.) 1 79.9 37 1 10.9 35.2 1 5.0 Acid number l 19. 9 l 4. 85 1 1. 207. l 1. 40

1 Average of a plurality of tests.

From these data it can be observed that a lubricating oil compositionwas produced from a highly corrosive neutral oil and a moderatelycorrosive bright stock and the resulting composition showed superiorqualifications for aircraft engine lubrication as evidenced by the Mac-Coull-Ryder test.

EXAMPLE II To show the effect of the use of excessive amounts of acidactivated and neutral clays on the neutral oil, a straight run neutraloil having a viscosity of 525 SUS at 100 F. and obtained by phenolextracting and methylethylketone dewaxing a neutral oil fraction from avacuum still distillation of a Mid-Continent crude oil was divided intoseveral samples. The first sample was not contacted; a second sample wascontacted with 24 pounds of Filtrol No. 70 per barrel; a third samplewas contacted with 30 pounds of attapulgus clay per barrel; a fourthsample was contacted with 3 pounds of Filtrol No. 70 and 30 pounds ofattapulgus clay per barrel; and a fifth sample was contacted with 3pounds of the Filtrol and 9 pounds of attapulgus clay per barrel.Significant data obtained in these tests are as vfollows:

Table II No Filtrol Attapulgus Dual-with contact contact contactexcessive Dual contact attapulgus Filtrol dosage, IbJbbl 3. Attapulgusdosage, lbJbbL-.. 9. Contact temp., F Filtrol-350.

Atta.300 Atta.300. MacCoull-Ryder test:

Lead hearing loss, Lugs l, 218 1 l, 350 1 1, 117 1,159, 1,045 n... 239.Viscosity increase (SUS/210 F.)- 62. 5 1 68.3 1 65. 5 89.0, 80.4. Acidnumber 19. 9 1 20. 9 1 21.6 20.5, 20.0-

'Average of a plurality of tests.

mass to remove light ends; the slurry was filtered and the treatedbright stock recovered.

The thus treated neutral oil and bright stock were then blended bymixing at ambient temperature to result in a blend containing 39 volumepercent neutral oil and 61 volume percent bright stock. The blend washeated to 320 F. and attapulgus clay was slurried into the blend in anamount equivalent to 3 pounds per barrel of blend. After a period ofagitation the mixture was steam stripped with steam at 320 F. andtheslurry was then filtered to remove the clay; the treated blend wasrecovered as product.

Tests were conducted on the Filtrol treated neutral oil, the untreatedbright stock, the Filtrol treated bright stock, the blend of Filtroltreated neutral oil and bright stock and the dual treated finished oilcompositions. The data obtained are:

EXAMPLE III In another experiment, lubricating oil compositions wereproduced by identical procedures except that in one run the componentswere dual treated and then blended while in a second run, the componentswere first blended and then subjected to the clay treatment. Dataobtained are:

From these data it is apparent that improved lubricating oilcompositions are produced by application of my dual contact method tothe components individually or to a blend of the components.

I claim:

1. The method of producing non-additive aircraft engine lubricating oilcompositions consisting essentially of about 5 to 50 volume percent of arefined neutral oil of a viscosity of about 300 to 600 SUS at 100 F. and50 to 95 volume percent of a refined heavy mineral lubricating oilfraction of a viscosity of about 80 to 200 SUS at 210 P. which comprisescontacting the refined neutral oil fraction with about 1 to 5 pounds ofacid activated clay per barrel at a temperature of about 325 to 450 F.,stripping said contacted neutral oil of components boiling attemperatures up to about 700 F., separating the neutral oil from theclay, contacting the refined heavy lubricating oil With about 4 to 8pounds of acid activated clay per barrel at a temperature of about 500to 600 F., stripping said contacted heavy lubricating oil of componentsboiling at temperatures up to about 700 F., separating the heavylubricating oil from the clay, contacting each of the acid clay-treatedneutral oil and heavy lubricating oil components with about 2 to 15pounds of a neutral clay per barrel at a temperature of 275 to 350 F.,separating the oil coniponents from the neutral clay and blending therecovered oil components to obtain a lubricating oil composition.

2. The method of claim 1 wherein said neutral-clay treatedcomponents arealso stripped of components boiling at temperatures up to about 700 F.

3. The method of producing non-additive aircraft engine lubricating oilcompositions consisting essentially of about 5 to volume percent of arefined neutral oil of about 300 to 600 SUS at 100 F. and 50 to 95volume percent of a refined heavy mineral lubricating oil fraction ofabout to 200 SUS at 210 F. which comprises contacting the refinedneutral oil fraction with about 1 to 5 pounds of acid activated clay perbarrel at a temperature of about 325 to 450 F., stripping said contactedneutral oil of components boiling at temperatures up to about 700 F.,separating the neutral oil from the clay, contacting the refined heavylubricating oil With about 4 to 8 pounds of acid activated clay perbarrel at a temperature of about 500 to 600 F., stripping said contactedheavy lubricating oil of components boiling at temperatures up to about700 F., separating the heavy lubricating oil from the clay, blending theacid clay-treated neutral oil and heavy lubricating oil components,contacting the resulting blend with about 2 to 15 pounds of a neutralclay per barrel at a temperature of 275 to 350 F., separating the blendof oil components from the neutral clay to obtain the lubricating oilcomposition.

4. The method of claim 3 wherein the neutral claytreated blend ofneutral oil and heavy lubricating oil also is stripped of componentsboiling at temperatures up to about 700 F.

References Cited in the file of this patent UNITED STATES PATENTS2,067,334 Osterstrom Jan. 12, 1937 2,293,591 Chenault Aug. 18, 19422,461,454 Toettcher Feb. 8, 1949 2,594,880 Davis Apr. 29, 1952 2,695,865Mills Nov. 30, 1954 2,726,997 Dudley et a1. Dec. 13, 1955

1. THE METHOD OF PRODUCING NON-ADDITIVE AIRCRAFT ENGINE LUBRICATING OIL COMPOSITIONS CONSISTING ESSENTIALLY OF ABOUT 5 TO 50 VOLUME PERCENT OF A REFINED NEUTRAL OIL OF A VISCOSITY OF ABOUT 300 TO 600 SUS AT 100*F. AND 50 TO 95 VOLUME PERCENT OF A REFINED HEAVY MINERAL LUBRICATING OIL FRACTION OF A VISCOSITY OF ABOUT 80 TO 200 SUS AT 210*F. WHICH COMPRISES CONTACTING THE REFINED NEUTRAL OIL FRACTION WITH ABOUT 1 TO 5 POUNDS OF ACID ACTIVATED CLAY PER BARREL AT A TEMPERATURE OF ABOUT 325 TO 450*F., STRIPPING SAID CONTACTED NEUTRAL OIL OF COMPONENTS BOILING AT TEMPERATURES UP TO ABOUT 700* F., SEPARATING THE NEUTRAL OIL FROM THE CLAY, CONTACTING THE REFINED HEAVY LUBRICATING OIL WITH ABOUT 4 TO 8 POUNDS OF ACID ACTIVATED CLAY PER BARREL AT A TEMPERATURE OF ABOUT 500 TO 600*F., STRIPPING SAID CONTACTED HEAVY LUBRICATING OIL OF COMPONENTS BOILING AT TEMPERATURES UP TO ABOUT 700*F., SEPARATING THE HEAVY LUBRICATING OIL FROM THE CLAY, CONTACTING EACH OF THE ACID CLAY-TREATED NEUTRAL OIL AND HEAVY LUBRICATING OIL COMPONENTS WITH ABOUT 2 TO 15 POUNDS OF A NEUTRAL CLAY PER BARREL AT A TEMPERATURE OF 275 TO 350*F., SEPARATING THE OIL COMPONENTS FROM THE NEUTRAL CLAY AND BLENDING THE RECOVERED OIL COMPONENTS TO OBTAIN A LUBRICATING OIL COMPOSITION. 